Clamp



FIG. 1 is a perspective view of a clamp showing my new design;

FIG. 2 is a front view thereof, a rear view being the same as the front view;

FIG. 3 is a right side view thereof, a left side view being the same as the right side view;

FIG. 4 is a plan view thereof; and,

FIG. 5 is a bottom view thereof. 

The ornamental design for a clamp, as shown and described. 